Electric switch



Jan. 26, 1954 L. GRIFFITHS 2,667,544

ELECTRIC SWITCH Filed April 2, 1951 Inventor":

.Leonar-d r'ifFit 5, 1

His Atbo 5 Patented Jan. 26, 1954 Leonard Griffiths, Stoke, Coventry, England, assignor to General Electric Company, a ool-potation nfiNew York hpplication-Aprilz, 1951, Serial K042183759 tric switch of 'the type having a plurality :of sta- 3 'Glaims. (o1. zoo-4r) ti nary vflexib e contac s and a rotor element for establishing an electrical circuit between the yarious flexible contacts.

Ibis inv ntion relates parti ul l to that typ sw tch us d fo con rol ng a .p ura'lity' f cuits. F r ex mpl it ref rs "to that pa i l r typ switch that can be used'fin automobiles or turn on light and i nition circuit o adios for switching on acts simultane s y in a n m r of circuits depending upon the broadcast band to be used- Switclhes o t s s rt must "b ine p siv yet sturdy, and certain of establishing good contact. a radio circuit. for exam le, any dirt or faulty contact existin etween the rotor d t tacting elements will produce'unwanted noise or dist ion.

Such switches are also siibjectto jarring if they are positioned. in a proving vehicle. Conseguently, c s de at on mu 'be made of establishin po iti e c nta t sp of ny p y l to provide a new and improved :plug connector which can be :securely'pos'itioned within a switch and which .is :engageable with a mating electric plug.

it is a still further object of this invention to provide a new and improved combination electrical connector andiswitch contact element made inone piece.

Further objects and advantages of this invention will become apparent and the invention will be more clearly understood from the following description referring to the accompanying draw- :ing and :the invention will she pointed out with particularityin the claims annexed to andform- .ing apart :of thissspec-ification.

Briefly, this invention comprises a molded :plastic "base having a plurality of sockets therein to receive plug connectors, :Pln c nn t rs are inserted into @thesocketsin the base and held there against long-itudinalmovemcnt :by aninterlocking tongue and groove structure. The plug connectors are so designed "as to provide an integral brush contact element and secure connotation for a plug connector.

Referring to the drawing, Fig, 1 is a perspective View of "the body portion of the switch (partially broken away) and the elements that fit into it; Fig. 2 is a sectional elevation of a'eomplete switch taken along line -2-2 in Fig. "3, while Fig. 3 is an end elevation of the'switch.

Referringto the drawing, this improved switch "is shown as comprising a"blocl :or base I, ap'lug connector 2, a mating'electric plug 3, and a'rotor 4 mounted with a spaced handle 5 on a shaft 6.

The block or base I is shown as comprising a disc of any insulating 'material, 'for example a phenolic resin plastic. Aplurality of openings or sockets are shown spaced apart along the circumference of an imaginary circle having the center of base I for its center. Each of the openings 1 in the body I has a particular configuration; s-pecifically, the opening 1 is shown as being primarily cylindrical "but including a groove 3 in the'wallthereof. "The groove -8 meets a second groove 9 having a greater width than that of groove .8 to provide a shoulder 10 at the abutting ends. These slots or grooves 8 and 9 are positioned to receive and interlock with an element of the plug connector 2 as will be described hereinafter.

Plug connectors Z, in a preferred embodiment, are stamped from phosphor bronze and shaped to provide a one piece plug connector comprising a generally cylindrical body which is engageable with the socket I inbase Ideally, the free diameter of the body II is slightly larger than the diameter of the opening I, "but the body H may be compressed until it fits into socket i, whereupon the natural resiliency of the phosphor bronze will expand the body 11 again to engage the side walls of the opening I. A tongu [2, a

portion of body H slides in the grocve'B'thereby allowing the plug connector to "be inserted into opening 1. After the tongue =|=2 h-asbeen inserted through the slot 8, it enters the larger slot e and then "by twisting the'plug connector 2, the tongue I2 engages shoulder I!) to hold the plug connector against longitudinal movement. Consequently, the combination of the resiliency of the phosphor bronze and interlocking of the tongue 12 with the shoulder I B provides a tight secure fit between the plug connector and base I.

The sockets Fl and grooves '23 and :9 are formed simultaneously with the molding of :base 1!. Consequently, problems are :not "encountered such as those experienced when metal inserts are cast into the block or base portion as has been done heretofore in the art.

The plug connector 2 is further provided preferably with an integral leaf-spring like extension I4 which supplies a brush contact element for establishing an electrical circuit between the plug connector and the rotor 4. Note that the springs I4 are so positioned that the rotor 4 tends to urge the body portion II of plug connector '2 to be twisted counterclockwise thereby maintaining tongue I2 in groove 9 and in engagement with shoulder I to further secure the plug connectors within base I.

The electric plug 3 is illustrated as an extruded cylinder having a central element I5, a groove I6, a shoulder I1, and an expanded end I8. An electrical conductor I9 of the usual sort having a wire 20 surrounded by insulation 2| is inserted into the plug 3 and secured as by solder at 23 to establish good electrical contact between the wire 20 and the plug 3.

Plug 3 is then axially insertable into the plug connector 2 until the shoulder II which has a larger diameter than the central portion I meets the end of the body II of the plug connector 2. The groove It in plug 3 registers with a finger 24 expressed from the body II of the plug connector 2 when the plug 3 is inserted into connector 2. Finger 24 is so shaped as to provide a resilient inwardly directed curve for establishing contact without providing catches which would resist the insertion of the plug 3.

The plug connector 2 has another finger 25 at the upper end of the body portion H which is crimped to have a smaller free diameter than the rest of the body portion, causing the finger 25 to be offset inwardly from the rest of the body portion as can be seen particularly in Fig. 1. When the plug 3 is inserted into the body portion II, the finger 25 is pushed radially outwardly to accommodate the body portion I5 of the plug 3, but the finger 25, because of its resiliency, and tendency to achieve its free diameter, exerts a diametric force on the body portion I5 of the plug 3. This diametric force exerted by the finger 25 in combination with the force exerted by the finger '24 gives a secure contact to the plug 3 in its relationship with the plug connector 2, thus preventing plug 3 from being dislodged from the plug connector 2 due to vibration or the like.

Rotor 4 has a diameter which provides free rotation in a bore 4a positioned centrally of base I. The depth of the rotor 4 is such that a portion of it will stick out from the base I to make contact with the leaf-springs I4 on the plug connectors 2. To provide this electrical contact, electrically conducting inserts 26, 21, and 28, etc. formed inthe shape of arcs of circles are embedded in the rotor 4. They are circumferentially positioned to make contact with selected leaf-springs I4 at particular positions of rotation of the rotor 4. The natural resiliency of the leaf-contacts I4 in engagement with the smooth inserts 26, 21, 28, etc. provides a secure and intimate electrical contact having properties that will resist much vibration. Obviously, the positioning of the inserts within the rotor 4 in any particular position is not to be any limitation on this invention and the material from which the inserts 26, 21, and 28 are formed is not to be considered a limitation on this invention. For example, instead of inserts, strips of copper could be screwed or riveted to the rotor 4 and need not be molded in it.

. base I.

The rotor 4 can be secured to the shaft 8 through any of the conventional means. For example, the rotor 4 can be molded directly on the shaft Ii whereupon the bottom of the shaft would be provided with serrations 29 to assure good contact between the shaft and the rotor 4. In another embodiment, the rotor 4 could have a set screw which would position it on the shaft 6. Shaft 6 is of a size which permits its free movement within a bore 29a centrally positioned in base I of the switch and it has a groove 30 which registers with the upper surface of the body I. A clip ring 3| is inserted into this groove 311. after the shaft has been positioned through the body I to prevent the rotor 4 from being axially withdrawn from the Note too, that a spring 32 and ball 33 is maintained within the body I in a bore 34 to exert a pressure against the rotor 4 thereby keeping it from binding with the bottom of the base I. This insures a free movement of the rotor 4 relative to the base I and simple and smooth contact between the inserts 26, 21, and '28 and the leaf-springs I4.

The shaft 6 is passed through a bore 35 in a cover plate 33 which in turn is secured by a plurality of screws,3I to the base I. This structure permits the connection of the switch to a metal plate 38 for example which has an aperture large enough to receive the base I. In one embodiment, the upper surface of the base I has a rabbet cut therefrom to provide a shoulder which will not go through the plate 38 while allowing a portion of the base I to pass through the plate 38. Then, by putting the cover plate 36 over the metal plate 38 and securing the cover plate 36 to the base I by means of the screws 31, the switch is prevented from movement relative to the plate and is securely held thereto.

The only other element added to this switch is the handle 4| which is secured to shaft 6 by any sort of a pin 42 to provide for the rotation of the shaft 5 and hence the rotor 4. Obviously, an indicator can be put on the handle 4| to align the handle with the desired electrical contacts that are intended to be made.

Modifications of this invention will occur to those skilled in the art and it is desired to be understood, therefore, that the invention is not intended to be limited to the particular embodiment disclosed, but rather is it intended to cover all modifications which are within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is z 1. An electrical switch comprising a base of insulating material, a plurality of plug connectors each including a spring contact, electric plugs engageable with said plug connectors and a rotor including electrical conducting inserts for interconnecting the spring contacts of said plug connectors, said base defining a plurality of sockets spaced around the circumference of a circle, each of said sockets having a pair of interacting grooves in a wall thereof with one of said grooves having a larger width than the other to provide a shoulder, said plug connector including an integral body portion of resilient material having a tongue extending therefrom slideable within said grooves and engageable with saidshoulder 'to prevent the axial withdrawal of said plug congagement with said shoulder thereby to prevent withdrawal of said plug connector from said base.

2. An electrical switch comprising a base of insulating material, a plurality of plug connectors each including a spring contact, electric plugs engageable with said plug connectors and a rotor including electrical conducting inserts for interconnecting the spring contacts of said plug connectors, said base defining a plurality of sockets spaced around the circumference of a circle, each of said sockets having a pair of interacting grooves in a wall thereof with one of said grooves having a larger width than the other to provide a shoulder, said plug connector including an integral body portion of resilient material having a tongue extending therefrom slideable within said grooves and engageable with said shoulder to prevent the axial withdrawal of said plug connector from said base, said spring contact portion of said plug connector when in engagement with said rotor acting to bias said tongue into engagement with said shoulder thereby to prevent withdrawal of said plug connector from said base,

said plug connector further comprising a resilient finger capable of interlocking with a circumferential groove on said electric plug to prevent said plug from vibrating out of said plug connector.

3. In an electrical switch, as is recited in claim 2, wherein an inwardly directed resilient finger is provided on the plug connector to frictionally engage the body of the said electric plug over a large area to assist in preventing said plug from vibrating out of said plug connector.

LEONARD GRIFFITHS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,219,878 Turck Oct. 29, 1940 2,259,326 Schmid Oct. 14, 1941 2,319,651 Penfold May 11, 1943 2,449,765 Brattain Sept. 21, 1948 2,472,131 Toth et a1 June 7, 1949 

